// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_PUBLIC_BROWSER_RENDER_PROCESS_HOST_OBSERVER_H_
#define CONTENT_PUBLIC_BROWSER_RENDER_PROCESS_HOST_OBSERVER_H_

#include "base/process/kill.h"
#include "base/process/process_handle.h"
#include "content/common/content_export.h"

namespace content {

class RenderProcessHost;

// An observer API implemented by classes which are interested
// in RenderProcessHost lifecycle events.
class CONTENT_EXPORT RenderProcessHostObserver {
public:
    // This method is invoked when the process was launched and the channel was
    // connected. This is the earliest time it is safe to call Shutdown on the
    // RenderProcessHost and get RenderProcessExited notifications.
    virtual void RenderProcessReady(RenderProcessHost* host) { }

    // This method is invoked when the process is going to exit and should not be
    // used for further navigations. Note that this is a COURTESY callback, not
    // guaranteed to be called for any particular process. Because this is the
    // first step in an orderly shutdown of a render process, do not expect that
    // a new render process will be hosted with this RenderProcessHost.
    virtual void RenderProcessWillExit(RenderProcessHost* host) { }

    // This method is invoked when the process of the observed RenderProcessHost
    // exits (either normally or with a crash). To determine if the process closed
    // normally or crashed, examine the |status| parameter.
    //
    // A new render process may be spawned for this RenderProcessHost, but there
    // are no guarantees (e.g. if shutdown is occurring, the HostDestroyed
    // callback will happen soon and that will be it, but if the renderer crashed
    // and the user clicks 'reload', a new render process will be spawned).
    //
    // This will cause a call to WebContentsObserver::RenderProcessGone() for the
    // active renderer process for the top-level frame; for code that needs to be
    // a WebContentsObserver anyway, consider whether that API might be a better
    // choice.
    //
    // If |status| is TERMINATION_STATUS_LAUNCH_FAILED then |exit_code| will
    // contain a platform specific launch failure error code. Otherwise, it will
    // contain the exit code for the process.
    virtual void RenderProcessExited(RenderProcessHost* host,
        base::TerminationStatus status,
        int exit_code) { }

    // This method is invoked when the observed RenderProcessHost itself is
    // destroyed. This is guaranteed to be the last call made to the observer, so
    // if the observer is tied to the observed RenderProcessHost, it is safe to
    // delete it.
    virtual void RenderProcessHostDestroyed(RenderProcessHost* host) { }

protected:
    virtual ~RenderProcessHostObserver() { }
};

} // namespace content

#endif // CONTENT_PUBLIC_BROWSER_RENDER_PROCESS_HOST_OBSERVER_H_
